Bora Akgün

Abstract As part of its HL-LHC upgrade program, the CMS collaboration is developing a High Granularity Calorimeter (CE) to replace the existing endcap calorimeters. The CE is a sampling calorimeter with unprecedented transverse and longitudinal readout for both electromagnetic (CE-E) and hadronic (CE-H) compartments. The calorimeter will be built with ∼30,000 hexagonal silicon modules. Prototype modules have been constructed with 6-inch hexagonal silicon sensors with cell areas of 1.1 cm 2 , and the SKIROC2-CMS readout ASIC. Beam tests of different sampling configurations were conducted with the prototype modules at DESY and CERN in 2017 and 2018. This paper describes the construction and commissioning of the CE calorimeter prototype, the silicon modules used in the construction, their basic performance, and the methods used for their calibration.

Abstract The upgrade of the CMS experiment for the high luminosity operation of the LHC comprises the replacement of the current endcap calorimeter by a high granularity sampling calorimeter (HGCAL). The electromagnetic section of the HGCAL is based on silicon sensors interspersed between lead and copper (or copper tungsten) absorbers. The hadronic section uses layers of stainless steel as an absorbing medium and silicon sensors as an active medium in the regions of high radiation exposure, and scintillator tiles directly read out by silicon photomultipliers in the remaining regions. As part of the development of the detector and its readout electronic components, a section of a silicon-based HGCAL prototype detector along with a section of the CALICE AHCAL prototype was exposed to muons, electrons and charged pions in beam test experiments at the H2 beamline at the CERN SPS in October 2018. The AHCAL uses the same technology as foreseen for the HGCAL but with much finer longitudinal segmentation. The performance of the calorimeters in terms of energy response and resolution, longitudinal and transverse shower profiles is studied using negatively charged pions, and is compared to GEANT4 predictions. This is the first report summarizing results of hadronic showers measured by the HGCAL prototype using beam test data.

Abstract The Compact Muon Solenoid collaboration is designing a new high-granularity endcap calorimeter, HGCAL, to be installed later this decade. As part of this development work, a prototype system was built, with an electromagnetic section consisting of 14 double-sided structures, providing 28 sampling layers. Each sampling layer has an hexagonal module, where a multipad large-area silicon sensor is glued between an electronics circuit board and a metal baseplate. The sensor pads of approximately 1.1 cm 2 are wire-bonded to the circuit board and are readout by custom integrated circuits. The prototype was extensively tested with beams at CERN's Super Proton Synchrotron in 2018. Based on the data collected with beams of positrons, with energies ranging from 20 to 300 GeV, measurements of the energy resolution and linearity, the position and angular resolutions, and the shower shapes are presented and compared to a detailed Geant4 simulation.

Abstract Scintillator samples are synthesized by a university-SME collaboration and the light yield, light emission and light transmission properties are studied with the aim of determining the fluor content that gives the highest light yield. Three plastic scintillator samples with different fluor additives are produced and their optical properties are found to be comparable with a high-light-yield EJ-204 reference sample. Amongst the three, the sample with 0.75\% PPO + 0.75 \%PTP and 0.04\% POPOP + 0.04\% Bis-MSB provides the highest light yield. The authors plan to use the same fluor additive concentration to produce application-specific scintillators that are not commercially available for nuclear reactor monitoring and medical applications.

Abstract The CMS experiment at the CERN LHC will be upgraded to accommodate the 5-fold increase in the instantaneous luminosity expected at the High-Luminosity LHC (HL-LHC) [1]. Concomitant with this increase will be an increase in the number of interactions in each bunch crossing and a significant increase in the total ionising dose and fluence. One part of this upgrade is the replacement of the current endcap calorimeters with a high granularity sampling calorimeter equipped with silicon sensors, designed to manage the high collision rates [2]. As part of the development of this calorimeter, a series of beam tests have been conducted with different sampling configurations using prototype segmented silicon detectors. In the most recent of these tests, conducted in late 2018 at the CERN SPS, the performance of a prototype calorimeter equipped with ≈12,000 channels of silicon sensors was studied with beams of high-energy electrons, pions and muons. This paper describes the custom-built scalable data acquisition system that was built with readily available FPGA mezzanines and low-cost Raspberry Pi computers.

The CMS pixel detector phase 1 upgrade in 2017 requires an upgraded data acquisition (DAQ) system to accept higher data rates. A new DAQ system has been developed based on a combination of custom and standard μTCA parts. Custom mezzanines on FC7 AMCs [1] provide a front-end driver for readout, and a front-end controller for configuration, clock and trigger. The DAQ system is undergoing a series of integration tests including readout of the pilot pixel detector already installed in CMS, checkout of the phase 1 detector during its assembly, and testing with the CMS central DAQ. This paper describes the DAQ system, integration tests and results, and an outline of the activities up to commissioning the final system at CMS in 2017.

Facing and experiencing the recent mucilage event in the Sea of Marmara-Türkiye in 2021 urged the local and state officers together with the related authorities to strengthen and improve the existing environmental auditing system.It is well-known that high pollution loads discharged to the receiving sea environment through land-based sources of point and diffuse loads accelerated the formation of mucilage in line with the warming of the sea surface as a consequence of climate change.In this regard changes, revisions, and particularly sector-specific activities were funded through a project established by the Ministry of Environment, Urbanization, and Climate Change (MoEU) and carried out by a group of academics and MoEU technical specialists.As such, the auding system has been thoroughly improved to prevent further deterioration of the Sea of Marmara surrounded by 7 metropolitan provinces of the country.This study is on the lessons-learnt during the renewal attempts of the auditing system with the aim of benefiting from the recent applications of the other developing and/or regional countries suffering from coastal pollution.

As part of its HL-LHC upgrade program, the CMS collaboration is replacing its existing endcap calorimeters with a high-granularity calorimeter (CE). The new calorimeter is a sampling calorimeter with unprecedented transverse and longitudinal readout for both electromagnetic and hadronic compartments. Due to its compactness, intrinsic time resolution, and radiation hardness, silicon has been chosen as active material for the regions exposed to higher radiation levels. The silicon sensors are fabricated as 20 cm (8") wide hexagonal wafers and are segmented into several hundred pads which are read out individually. As part of the sensor qualification strategy, 8" sensor irradiation with neutrons has been conducted at the Rhode Island Nuclear Science Center (RINSC) and followed by their electrical characterisation in 2020-21. The completion of this important milestone in the CE's R&D program is documented in this paper and it provides detailed account of the associated infrastructure and procedures. The results on the electrical properties of the irradiated CE silicon sensors are presented.

The CMS phase 1 pixel upgrade is planned for installation in 2016-2017, incorporating new frontend ASICs with digital 400 Mbps data links to handle a higher instantaneous luminosity of up to 2.5 x 10 34 cm -2 s -1 and trigger rates of 100 kHz with bunch spacing scenarios of 25 or 50 ns.The new digital readout requires new back-end electronics incorporating faster optical receivers and firmware for decoding the new data format.Additionally the phase 1 upgrade is powered from DC-DC converters installed inside CMS close to the modules.To gain experience with this new readout chain and DC-DC converters under realistic operating conditions (trigger rates, backgrounds, high data occupancy, and possible single-event upsets) a pilot detector system comprising eight sensor modules, service electronics, optical links, and back-end electronics has been prepared using pre-production parts.The pilot system was installed with the present forward pixel detector in 2014 during long shutdown 1 (LS1).The pilot system will be operated concurrently with the present pixel detector in 2015-2016 to validate the data acquisition and powering design and advance online control system development for a rapid deployment of the full detector in 2017.This report summarizes the phase 1 pilot system experience leading into Run 2 of the LHC.

The production of J /ψ and Υ mesons is studied in pp collisions at \surds = 7 TeV with the CMS experiment at the LHC. The J /ψ measurement is based on a dimuon sample corresponding to an integrated luminosity of 314 nb^{-1}. The J /ψ differential cross section is determined, as a function of the J/ψ transverse momentum, in three rapidity ranges. A fit to the decay length distribution is used to separate the prompt from the non-prompt (b hadron to J/ψ) component. Integrated over the J /ψ transverse momentum from 6.5 to 30 GeV/c and over rapidity in the range |y| < 2.4, the measured cross sections, times the dimuon decay branching fraction, are 70.9 \pm 2.1(stat.) \pm 3.0(syst.) \pm 7.8(lumi.) nb for prompt J /ψ mesons, assuming unpolarized production, and 26.0 \pm 1.4(stat.) \pm 1.6(syst.) \pm 2.9(lumi.) nb for J /ψ mesons from b-hadron decays. The Υ measurement is based on a dimuon sample corresponding to an integrated luminosity 3.1 \pm 0.3 pb^{-1}. Integrated over the rapidity range |y| < 2, we find the product of the Υ(1S) production cross section and branching fraction to dimuons to be 7.37 \pm 0.13(stat.)^{+0.61}_{-0.42}(syst.) \pm 0.81(lumi.) nb. This cross section is obtained assuming unpolarized Υ(1S) production. If the Υ(1S) production polarization is fully transverse or fully longitudinal, the cross section changes by about 20 %.

The observation of a new b baryon via its strong decay into Ξ - b π + (plus charge conjugates) is reported.The measurement uses a data sample of pp collisions at √ s = 7 TeV collected by the CMS experiment at the LHC, corresponding to an integrated luminosity of 5.3 f b -1 .The new state most likely corresponds to the J P = 3/2 + companion of the Ξ b .A flavour-untagged measurement of the lifetime difference in the B s → J/ψφ with J/ψ → µ + µ - and φ → K + K -decay is presented.Assuming the mixing phase φ s to be zero, we obtain a decay width difference ∆Γ s = 0.048 ± 0.024 (stat.)± 0.003 (syst.)ps - between the two B s mass eigenstates.The Λ b differential production cross section and the cross-section ratio σ ( Λb )/σ (Λ b ) are measured as functions of transverse momentum p Λ b T and rapidity |y Λ b | in pp collisions at √ s = 7 TeV.The measurements are based on Λ b decays reconstructed in the exclusive final state J/ψΛ, with the subsequent decays J/ψ → µ + µ -and Λ → pπ, using a data sample corresponding to an integrated luminosity of 1.9 f b -1 .

Climate change is a reality of today. Paleoclimatic proxies and climate predictions based on coupled atmosphere-ocean general circulation models provide us with temperature data. Using Detrended Fluctuation Analysis, we are investigating the statistical connection between the climate types of the present and these local temperatures. We are relating this issue to some well-known historic climate shifts. Our main result is that the temperature fluctuations with or without a temperature scale attached to them, can be used to classify climates in the absence of other indicators such as pan evaporation and precipitation.

It is anticipated that the LHC accelerator will reach and exceed the luminosity of L=2×1034 cm−2s−1 during the LHC Run 2 period until 2023. At this higher luminosity and increased hit occupancies the CMS phase-0 pixel detector would have been subjected to severe dead time and inefficiencies introduced by limited buffers in the analog read-out chip and effects of radiation damage in the sensors. Therefore a new pixel detector has been built and replaced the phase-0 detector in the 2016/17 LHC extended year-end technical stop. The CMS phase-1 pixel detector features four central barrel layers and three end-cap disks in forward and backward direction for robust tracking performance, and a significantly reduced overall material budget including new cooling and powering schemes. The design of the new front-end readout chip comprises larger data buffers, an increased transmission bandwidth, and low-threshold comparators. These improvements allow the new pixel detector to sustain and improve the efficiency of the current pixel tracker at the increased requirements imposed by high luminosities and pile-up. A new DAQ system has been developed based on a combination of custom and standard microTCA parts. This contribution gives an overview of the design and performance of the CMS phase-1 pixel detector.

As part of its HL-LHC upgrade program, the CMS Collaboration is developing a High Granularity Calorimeter (CE) to replace the existing endcap calorimeters. The CE is a sampling calorimeter with unprecedented transverse and longitudinal readout for both electromagnetic (CE-E) and hadronic (CE-H) compartments. The calorimeter will be built with $\sim$30,000 hexagonal silicon modules. Prototype modules have been constructed with 6-inch hexagonal silicon sensors with cell areas of 1.1~$cm^2$, and the SKIROC2-CMS readout ASIC. Beam tests of different sampling configurations were conducted with the prototype modules at DESY and CERN in 2017 and 2018. This paper describes the construction and commissioning of the CE calorimeter prototype, the silicon modules used in the construction, their basic performance, and the methods used for their calibration.

We present a digital bus configuration for multi-processor systems with square pyramid structure. Multi-processor systems with square pyramid structure are closely coupled. Therefore, nodes should not access the same memory location simultaneously. This restriction let us present a simple and efficient bus configuration for interconnecting shared memory units of the multi-processor system. We implement a prototype of a presented system, for real time applications. In addition, for an efficient use of hardware, we implemented a distributed shared memory management software using the message passing technique for the communications between the software modules situated at different nodes.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>